Regulating means for fuel oil heating systems



Q Aprll 25, 1950 o, MULLER S 05 REGULATING MEANS FOR FUEL OIL HEATINGSYSTEMS Filed June 28, 1945 2 Sheets-Sheet l LIGHT OIL HEAVY 0/1.

-0Z Z'0 Muller WWW P 1950 o. MULLER 2,505,298

REGULATING MEANS FOR FUEL OIL HEATING SYSTEMS Filed June 28, 1945- I I 2Sheets-Sheet 2 0270 Muller yw W Patented Apr. 25, 1950 REGULATIN G MEANSFOR FUEL OIL HEATING SYSTEMS Otto Muller, Bronx, N. Y.

Application June 28, 1945, Serial No. 601,969

3 Claims.

This invention relates generally to the art of heating and moreparticularly to an improved fuel oil heating system and is acontinuation in part of my copending application Serial No. 414,901,filed October 13, 1941, abandoned July 11, 1945, for Fuel oil heatingsystems.

One of the principal objects of the invention is'to provide a fuel oilheating system wherein provision is made for starting the oil burneremployed on relatively light oil and, after a desired temperature hasbeen reached, automatically changing to a heavier oil.

Another object of the invention is to provide a fuel oil heating systemby the use of which it will be possible to burn fuel oil of a volatilitywhich requires pre-heating without the need of large separatepre-heaters and other cumbersome equipment.

Another object of the invention is to provide a fuel oil heating systemwhich will operate with equal efficiency with rotary type burners andboth high and low pressure nozzle type burners.

A further object is to provide a system of this character including thestep of scavenging relatively cold oil from the burner before the sameis supplied with oil of the proper temperature.

A further object of the invention is to provide 7 a heating system ofthe type set forth wherein there is included the step of scavengingrelatively heavy oil from the burner before the same is started onrelatively light oil.

A further object of the invention is to provide a heating system of thetype set forth herein wherein there is included the step of scavengingrelatively heavy oil from the burner at the end of the running periodand leaving it empty of oil, same to be supplied with and started onrelatively light oil.

A further object of the invention is to provide a heating system of thetype set forth wherein is ncluded the step of scavenging relativelyheavy oil from the burner at the end of each running period, anddelivering a charge of relatively light oil to the burner beforeoperation ceases, this relatively light oil being used for starting theburner for the next operating period.

A further object of the invention is to provide a heating system of thetype set forth wherein there is included the step of scavengingrelatively heavy oil from the burner before the same is started onrelatively light oil and which provides a means of circulating heavy oilthrough heaters (heated by the burning of the light oil) until the heavyoil has reached a predetermined temperature.

A further object of the invention is to provide a heating system whereinthe steps of scavenging, starting on light oil, heating heavy oil,circulating heavy oil for heating purposes, and changing from light toheavy oil when the heavy oil has reached a predetermined temperature,are accomplished entirely automatically.

A further object of the invention is toprovide a heating system whereinthe steps of scavenging, starting on light oil, heating heavy oil,circulating heavy oil for heating purposes, and changing from light toheavy oil are accomplished automatically each time the burner is startedregardless of the temperature of the oil in the system.

A further object of this invention is to provide a heating systemwherein the step of scavenging at the end of the running period, leavingthe burner empty of oil during idle periods, starting on light oil,heating heavy oil, circulating heavy oil for heating purposes, andchanging from light to heavy oil, are accomplished automatically eachtime the burner is stopped and started regardless of the temperature ofthe oil in the system.

A further object of the invention is to providea heating system whereinthe steps of scavenging rangement of my improved fuel oil heating sys-'tern, the burner employed being of the low pressure rotary type, and

The diagram shown as Figure 2 discloses th electrical means ofcontrolling the control valves 6, 20 and 25 shown in Figure 1.

Referring to Figure 1, the aforementioned m0 tor may be used to driveboth the pump l2 and the rotary burner I. At this point, it should bementioned that separate motors can be used to drive the pump 12 and theburner I, in which case the second motor is connected in parallel withthe first.

Referring to Figure 2, the aforementioned motor is used to drive thepump M. In thiscase, the burner 29 is a stationary nozzle tyiperequiring no motor.

.The aforementioned ignition apparatus is the standard equipment that ispart of the burner I shown in Figure 1. This ignition apparatus usuallyconsists of a gas torch, which is constantly lit as a small flame, andwhich is expanded to the proper size flame required for ignition duringthe ignition period.

Referring now more particularly to the drawings and to Figure 1 thereofwherein my improved sit f asapplied to 1t pressure rotary type burners,is shown; the numeral I indicates in general the burner. The burner I isof conventional design and is mounted in a boiler 2-, said boiler beingshown in dotted lines. At; is shown an oil tank. This tank is to containoil of light volatility and will be hereinafter designated as the lightoil tank. The tank '3 is connected with the burner l by a pipe Mountedin the pipe 4 beneath the tank is a regulating valve 5 which is ofconventional design. Also mounted in the pipe 4, between the valve 5.and the burner I. is a control valve 6 which is preferably operated. bya solenoid. In thiscorinection, it is desired particularly to point outthat the valve 6 may be operated manually, by a con'1'}t 'ressed aircylinder, steam cyiinder or by afiy other suitable means. In otherwords, I do not desire to limit myself to the use of a so'iricid.

At B-is shown a pressure regulator which is of desired and well knownconstruction. The pressure--re'gulator 8 is connected with a second oiltank 9,-which will be hereinafter designated as a heavy oil tank, by areturn pipe line II]. The heavy oil taiik 9 is also connected with theintake I I of a fuel pump I2 by a pipe I3. The pump I12 or the-positivepressure gear type of conventitii ial construction; through which no oilcan flow it"is not operation. A pipe I4 connects the discharge I5 of thepump with the pressure regiiietei '8. The pipe I4 else is connected withaeipe' it which is connected tothe inlet of an oil heater I! which ismounted in the boiler 2 or connected externally thereto. he outlet ofthe oil heater I! is connected with a regulating valve I8 Hy-a pipelathe valve being similar to the valve 5.

20 is shown a control valve which is similar ih 'ohstruet dn to thevalve t and is operated by Iioid although, as stated in connection withscription of the valve 6, said valve may be operated by other means. Apipe 22 leads from I the iliit hrt e Valve 20 to the outlet of the regulatifig valve I8, while another pipe 23 leads from the outlet of theValve 20 tothe burner I.

pipe 24 leads from the pipe I3 to the outlet of a control valve 25 whichis operated by a solenoid and is of similar construction to the valves 6and 2b. 'rhe inlet er the valve 25 is connected by a pipe 21-, to thepipe 22. V V

ere'in'b'efore pointed out, although the valves 6, 20 and 25 are shownas being operated by solerioids, said valves may be operated by othermeans. However, when the valves are operated by the solenoids, saidsolenoids will be effectively controlled as'indicated in the diagramshown as Figure 2 ens described hereinafter. The wirin is conventionaland may be varied to "suit particular conditions.

The operation of this embodiment of the inventicii will now be describedin more detail. Heavy oil, from a previous period of operation of theburner I, is first scavenged from said burner in thelfoll'owing manner;The valve 20 is allowed toremain open as is the valve 25. However, thevalve 6 is closed. The fuel pump I2 is first placed in operation, andduring. the scavenging period,

the pump will draw the heavy oil from the burner through the pipe 23,the valve 20, the pipes 22 and 21, the valve 25 and the pipes 24 and IIand delivered to the pump I2 and to the heavy oil tank 9 through thepipe I4, regulating valve 8, and pipe I0. It will thus be seen that,prior to starting the burner, all heavy oil is removed therefrom. Duringthis period, very little oil is drawn through the pipe l9 due to therestriction of the regulating valve IS. The capacity of the pump I2 isgreater than the amount of oil that will be permitted to flow throughthe regulating valve I8 at any time, therefore, during the scavengingoperation when valves 20 and 25 are open, and valve 6 is closed, thepump will draw the oil from the burner I because the atomizing unit ofthis burner is opento atmospheric pressure and will permit the pump todraw all the oil out. A certain amount of oil will be drawn throughvalve I8, but as this amount is less than the capacity or the pump, theoil will also be taken from the burner- The oil taken from the burner Iand valve I 8 is discharged into thepipe I4 under pressure, and as thepipes I6 and I! can carry only an amount of oil equal to that removedfrom the valve I8, the oil in excess of that amount must necessarily beforced out through the valve 8, therefore, the amount of oil drawn fromburner I is discharged through valve 8 during the scavenging period..After this has been done, the burner is ready to start. The valve 25 isnow allowed to remain open, the valve 6 is now opened and the valve 20is now closed as indicated in the diagram shown as Figure 2 anddescribed hereinafter; Thus, during the starting period, light voil willflow by gravity from the light oil tank. throughthe pipe 4, theregulating valve 5, the valve 6 and to the burner I. thus be suppliedfor starting purposes. During this period, the pump I2 draws heavy oilthrough theo'il heater I'I, valve I8,'pipes I9 and 21, control valve 25.and pipes 24 and II. This oil is of course pumped through pipes I4 andIt to heater I'I, Dueto the fact that valve 20 is closed during thisperiod the pump, which cannot be satisfied through the regulating valve.I8, draws oil from the, tank '9 through pipe I3. This equivalent amountof oil is. discharged by the pump through the valve 8 and returned tothe tank through pipe ID."-

When the oil in the heater I1 and in the pipes leading from said heaterback to pump I2 has reached the desired temperature, the valve '20 willbe automaticallyopened. At the same time, the valves 25 andB, areautomatically closed as indicated inthe diagram shown as Figure 2 anddescribed'hereinafter, with the result that light oil from the tank 3will be shut oii andheaVy oil will be fed directly from. the heater I'I,regulating valve I8, pipes I9and 22, valve 20, and the pipe 23 to theburner I. Any surplus heavy oil will return to the tank 9 through thepipe I0.

During this continued operation, the pump I2 draws. the required heavyoil from tank 9 through pipes I3 and II',and discharges it through pipesI4 and I6 into the heater I! maintaining the pressure for which thepressure regulating valve 8 is set. The surplus oil is dischargedthrough the pressure regulating valve 8 and flows back to tank 9 throughpipe I0, thus delivering a cohsta'r t supply of oil to burner I fornormal operati'ng conditions.

The above description describes the cycle of operation wherein thescavengih'g cycle occurs at the beginning of the running period. It isto be Light oil will understood that the scavenging cycle can occur atthe end of th running period and that the burner can be left empty ofoil or supplied with a charge of light oil at the end of the runningperiod, it being only necessary to properly convertthe valves andcontrols to produce this condition.

It is desired particularly to call attention to the fact that, by theuse of my improved system, it will be possible to burn heavy fuel oilwithout employing separate pre-heaters or other cumbersome equipment.Moreover, it is also desired to point out that, in view of theparticular arrangement, the change over from the light oil to the heavyoil will be allowed to take place without interruption of the flame andWithout puff or smoke. My system may be adapted for use with heatingplants of moderate size as Well as with those of larger size.

.It is now desired to describe the means by which the aforementionedapparatus, shown on Figure 1, is electrically controlled.

Referring now particularly to Figure 2, the detail of operation is asfollows:

The apparatus 56 is an oil burner relay of conventional design which isused as an intermediary control between the thermostat and the oilburner equipment. This apparatus is actuated by the closing of thecircuit of a thermostat 51 or other means of control. The closing of thecircuit through the control apparatus 51 completes the circuit throughthe time delay switches 58, 59 and 65 and the relay 60.

The time delay switch 58 controls the timing of the scavenging period.The switch contacts are'normally open and are timed to close at the endof the scavenging period.

The time delay switch 59 controls the ignition apparatus 10. Thecontacts are normally closed and are timed to open at the end of theignition period.

The time delay switch 65 is the safety device which automaticallyinterrupts the main line circuit should ignition fail to occur within agiven period of time. This device mechanically locks the circuit openingcontacts and must be manually reset before further operation ispossible. The relay 60 controls the line circuit. The contact isnormally open, and, when closed, continues the circuit to the motor,ignition apparatus and the control valves.

. The apparatus 6| is a thermostatically controlled apparatus which isactuated by the temperature of the heavy oil and is installed to permitits actuating element to come in contact with the oil flowing throughthe pipe it after it leaves the heater IT. This apparatus may be eitherof the mercury tube contact type or the mechanical contact type. Theapparatus shown in the diagram is of the mercury tube type. It is soconstructed'that the tubes swing from one inclined position to another,causing the mercury therein to flow to the contacts and close thecircuit or to flow away from the contacts and open the circuit. Thetubes shown in the diagram are in the position they assume when theheavy oil is below the desired temperature. When the heavy oil reachesits desired temperature the tubes swing as indicated by the arrow to thehot position.

The apparatus 62 is also a thermostatically controlled apparatus whichis actuated by the heat of the burner flame. It may be located to comein contact with the hot gases of combustion in either thecombustionchamber, the flue passages, or the flue pipe of the boiler 2. Thisapparatus may be either of the mercury tube contact type or themechanical contact type. The apparatus shown in the diagram is of themercury tube type. It is so constructed that the tubes swing from oneinclined position to another, causing the mercury therein to flow to thecontacts and close the circuit, or to flow away from the contacts andopen the circuit. The tubes shown in the diagram are in the positionthey assume when there is no fire in the combustion chamber. Whencombustion takes place the heat causes the tubes to swin as indicated bythe arrow to the hot position.

The apparatus 6, 20 and 25 represents the electrical mechanism of thecontrol valves bearing the similar numbers shown in Figure 1. Thesecontrol valves may be operated manually, electrically, by compressedair, steam, or any other suitable means. The valves indicated in Figure2 are of the solenoid type, the mechanical closing and opening of whichis controlled by a solenoid magnet.

Valve 6 is of the normally closed type, while valves 20 and 25 are ofthe normally open type.

' The above described apparatus is interconnected electrically asindicated in diagram shown as Figure 2. The cycle of operation, from acold start, is as follows:

The control apparatus 5'! demands heat and closes the circuit whichcauses apparatus '56 to start to function. The time delay switch 58starts to close, the time delay switch 59 starts to open, and the relay63 immediately closes. The apparatus 8i and 52 are each in their coldposition. Under these conditions the scavenging period takes placebecause the valve 6 is mechanically closed, valve 20 is mechanicallopen, and valve 25 is mechanically open. During this time, the suctionof the pump l2 scavenges the heavy oil from the burner I through theunrestricted pipe connections 23, 22, 24 and H. Very little oil is drawnthrough the pipe connection l9 during this time due to the restrictionof the regulating valve it. This scavenging period continues until thetime delay switch 58 is closed at which time the circuit is completed tothe control valv 6 and the control valve 26, causing valve 6 tomechanically open and valve 2% to mechanically close. Valve 25 remainsopen. With valve 6 open, valve 2%] closed and valve 25 open, thescavenging ceases and light oil is supplied to the burner from light oiltank 3 through pipe line l, through the regulating valve 5 and the opencontrol valve 5. The pump suction does not influence the oil burner Ibecause valve 29 is closed. However, the suction of the pump continuesto draw oil through the heater ll and regulating valve is because thevalve 25 is open. Very little, if any, oil is drawn through pipe isduring this period due to the fact that the suction of pump i2 issatisfied by the gravity flow from heater H. During this period theignition of the light oil takes place and the burner continues tooperate on light oil until the heavy oil flowing through the heater Hand pipe l9 reaches the desired temperature and causes apparatus 6| tofunction.

At the time combustion of the light oil took place, the heat of theflame caused apparatus 52 to swing to its hot position. However, thetubes of apparatus 62 are so connected that they will not influence thecontrol valves as long as apparatus 6| remains in its cold position.

When the temperature of the heavy oil flowing through pipe line [9causes apparatus 6| to asasserts some its hot positidn, the circuitthrough the valve 25 is closed by the action or the top tube causing itto mechanically close. At the same time, the action of the middle tubeopens the circult through valve 8 causing it to mec anically close andalso opens the circuit through the valve Zllcadsing it to mechanicallyopen.

With thevalve 6 closed, the valve open, and the valve closed, the burnernow continues to function on the heated heavy oil instead of the lightoil. The burner is now in its normal operating condition, during whi'chtime the suction of the pump draws oil from the heavy oil tans 9,through pipe lines 13 and H and discharges same into pipe line M. Thepressure regulating valve 8 causes oil at proper pressure to now throughpipe [6 to the heater ll while the surplus foil returns to the tank athrough pipe line I5. oil flow through the heater and pipe line l9 iscontrolled by the regulating valve l8 which ermits the right amount ofoil to flow to the burner] through pipe 22, open control valve'20 andpipe 23. The burner continues to burn heavy oil until temp'eraturecontrol apparatus 51 has been satisfied.

Thus, this apparatus makes possible the use of oil of extremely highviscosity without the use of auxiliary heating apparatus.

The operation described in the previous paragraphs was the cycle ofoperation from a "mid boiler start. During normal operation, however,

the burner is often started under hot boiler conditions. During a hotboiler start the heavy oil will have been previously heated to therequired temperature and the apparatus 6] Will be in its hot position atthe beginning of the starting cycle. In this case, the tubes inapparatus 6| will not influence the control valves but rather the tubesin apparatus 62, which, as previously stated, function the same as thosein apparatus 5|, will, influence the control valves. During the hotboiler start, the apparatus 56 functions as during the cold boilerstart. The scavenging period is, therefore, the same also. However,immediately after the combustion of the light oil takes place, the heatof the flue gases actuates apparatus 62 which immediately causes theburner to assume its normal operation and it continuesto burn the heavyoil until the control apparatus 51 has been satisfied.

For the purpose of avoiding a complicated diagram, the motor circuit andthe ignition circuit have been omitted from Figure 2. These aredescribed later.

The foregoing is the detail explanation of the embodiment of my fuel oilheating system wherein the feature of the scavenging of the heavy oilfrom the burner is accomplished at the beginning of every running periodbefore light oil is supplied to the burner 'for starting purposes. Thevarious drawings and electrical diagrams show the equipment so connectedand constructed as to bring about the aforementionedsequence-ofoperation.

It is to be understood that my invention includes electrical equipmentembodiments as follows:

Equipment of similar material as described in the foregoing, but inwhich scavenging occurs at the end of each running period leaving theburner empty of oil until the next running period. at which time it issupplied with light oil for starting purposes, and heavy oil for normaloperating purposes.

'The feature of scavenging the heav oil'fiom, the burner-at theme of therunning period and 8 leaving the burner empty of enduring idle periods,and the feature of scavengin the heavy oil from the corner at the end ofthe running period, supplying a charge of light oil at the end of therunning DiiO'd and leaving the burner filled with light on during idleperiods is accomplished by a modification in relay 60 of apparatus 56(Figure 2) I In conclusion, I state that my equipment, as describedabdv, is applicable to all types of Oil burners, making "possible theuse, of heavy oil without manual attention and without the use of largeand expensive auxiliary heating equipment, which equipment is alsocostly to maintain. I wish also to point out that my apparatus, besidesassuring automatic ignition, is free from puffs and smok starts. Greatsavings are experien'ced through the use "of my apparatus because heavyoil costs considerably less per gal- 10h and contains more heat unitsper gallon. In addition to these savings, is the additional saving ofthe cost of manual operation necessary with other types of systems.Furthermore, my apparatus includes every possible safety precaution suchas the Continued ignition until the burner is properly functioning inits normal condition, and the safety device which makes it impossible todischarge excessive amounts of unburned oil either before ignition takesplace-or after ignition takes place, if, for 'anyreason, the flameshould fail.

I also wish to call attention to the minimum amount of service broughtabout byignition failure which would becommon to burners where i'gnitionof heavy oil is accomplished by small torches rather than a completelight oil fire-as in the case of my equipment.

What Iclaim is:

'1. A 'fuel oil heating system comprising a burner, a light oiltank, apipe connecting said light oil tank to said burner, a normally closedcontrol valve betwee'nsaid tank and :said burner, a heavy oil tank,pipes connecting said heavy oil tank to's'aid burner, a motor drivenpump between said heavy oil tank and said burner, an

oil heater operatively connected between said pump and said burner,.anorma'lly-open shut off valve betweensaid heaterand said burner, abypass pipe between said heater and said :pump, a normally'openby-pass'shut ofi valve in'sa id bypass pipe, a return pipe between saidpump and said heavy oil tank, and a pressure control valve in saidreturn ,pipe,a solenoid operator for -each of said valves, normallyclosed temperature -responsive "switchesconnected to the solenoids ofsaidcontrol and shutoff valves, a nor'mally open tem zveratureresponsive switch connected to the solenoid of said oy-pass shut onvalve, said switches being responsive to the heavy .oil temperature, asecond normally closed temperature responsive switch between said firstnormally closed switches and a source of current supply and a secondnormally-open temperatureresponsive switch between said first normallyopen switch and said current supply, said second named switchesbeing-responsive to the temperature of said burner, a thermostatcontrolswitch responsiveto the demand of said heating system between saidsecond named switches and said pump motor and said current supply sourceand a ing of said thermqstat switch, said control valve and said shut01? valve will be reversed upon closing of said time delay switchthereby supplying light oil to said burner for starting, said burnertemperature responsive switches then reversing upon temperature rise ofsaid burner, and said oil temperature switches reversing upon rise ofthe heavy oil temperature again reversing said shut OE and controlvalves and said by-pass valve for operation of said burner on heavy oil.

2. A fuel oil heating system as set forth in claim 1, a. normally openrelay connected in said supply circuit between said thermostat and saidsecond named switches, and a normally closed time delay switch connectedbetween said thermostat and said relay and operatively connected to anormal- 1y open burner temperature responsive switch, whereby saidcircuit will be opened upon failure of ignition of said burner after apredetermined time.

3. A fuel oil heating system as set forth in claim 1, including anormally open time delay switch connected to said thermostat, anelectric burner ignition control member operatively connected to saidlatter time delay switch for igniting said burner a determined timeafter closing of said thermostat and after the scavenging period.

OTTO MULLER.

10 REFERENCES CITED The following references are of record in the fileof this patent:

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